Gregory's Top Down (Constructivist) Theory - Perception Flashcards
What is perceptual set?
A bias or readiness to perceive some things rather than others
- brain perceives things in a certain way due to past experience, context etc
What do visual illusions demonstrate the brain doing?
Creates a hypothesis to explain sensory data
- we have a tendency to perceive 3-D objects from 2-D drawings
What are ambiguous figures?
These images have 2 possible explanations = brain alternates between the two, creates a hypothesis to interpret what we see
What is the Ponzo illusion?
Brain thinks it’s looking at a railway line, believes 2nd line is further away so must be longer
- eliciting a perception of depth
What is the Muller-Lyer
Creates a perception of depth = perceive one line as longer
- applying size constancy incorrect because we think we are either looking at the inside or outside of a building (carpentered environment)
How does N/N relate to Gregory’s theory?
His ideas all suggest we perceive things differently due to our experiences and the type of world we life in
How do Enysenck and Keene criticise Gregory in terms of N/N?
Showed if the fins on the Muller-Lyer are replaced by circulars we still fall for illusions = nature
What did Palmer do?
Showed Ps a kitchen scene and flashed an object onto the screen that was either: appropriate to the scene (a loaf of bread) or inappropriate (a drum)
What did Palmer find?
- Bread identified correct 84% of the time
- Drum less than 50%
What did Palmer conclude?
Shows perceptual set as a people were ready to see the bread but not the drum = perception not influenced by sensory data
(N/N debate)
How does PAS relate to Palmers study?
Pictures were ambiguous as they were black and white cartoons therefore it may have been very easy to mistake the drum for something else or not identify some other pictures
What did Turnbull do?
Studied Bambuti Pygmies who lived in dense forest so had no developed size constancy - no experience of looking at objects further away
What did Turnbull find?
Thought a buffalo grazing in the distance was an insect, involved in N/N debate as shows nurture
What does Gregory believe?
Our past experience, context, knowledge, expectations and motivations effect how we interpret visual info = nurture
